Analytical chemistry has been instrumental in providing healthier and more comfortable living for billions of people around the world. For example, samples of water, air, microorganisms, and tissues from plants and animals are analyzed for environmental protection purposes. In the medical field, samples of body tissues and physiological fluids are analyzed to provide information on patients, e.g., for diagnosis and for monitoring purposes. In the past, analyses were mostly done by collecting samples and bringing them to a laboratory for analysis by large, relatively expensive and complex pieces of equipment.
As an alternative to laboratory analysis, disposable test strips, e.g., lateral flow devices, similar to those used in home pregnancy tests, are employed in testing in the field, e.g., point-of-care testing. Test strips for detecting multiple analytes generally include multiple reagents located on a carrier member, in which each reagent changes color in the presence or absence of a particular analyte. The change in color provides a visual qualitative indication to a user as to whether or not the respective analyte is present in the sample. However, oftentimes it is difficult for the user to determine whether or not a color change has actually occurred. As a result, the user frequently has to redo the test, which can be frustrating.
Accordingly, a continuing need exists for improved devices and methods for detecting multiple analytes that are both easy to use and accurate, while also allowing for testing in the field, e.g., point-of-care testing.